The present invention relates to a pressure difference measurement transducers in general and more particularly to an improved transducer of this type which permits easier assembly.
A pressure difference transducer of the type with an inner housing divided into two parts transversely to its longitudinal axis, between the two housing sections of which is clamped a central diaphragm bearing a pressure sensor and whose one housing section contains an electric lead-through in a bore, an external extension of which lies in an enlarged part of the bore is known in the art.
For example, in the pressure difference measurement transducer disclosed in U.S. Pat. No. 4,135,408, the bore containing the electric lead-through runs transversely to the longitudinal axis of the measurement transducer from the outside to the inside. The bore is enlarged towards the outside so that the an external extension of the electric lead-through can be pressed against an internal shoulder. Between the external extension and the shoulder, an O-ring is laid in order to make a reliable seal to the outside. Since, in this known pressure difference measurement transducer, the full static pressure in the inside of the measurement transducer acts upon the electric lead-through, a solid screw is screwed within the bore against the external extension of the electric lead-through.
Another measuring device for pressure measurement, this one with an electric lead-through housed in a bore parallel to the longitudinal axis of the measurement transducer is described DE 34 37 668 A1. An external extension of the lead-through lies in an enlarged part of the bore toward the pressure loading, which in turn, on its side away from the pressure loading, becomes an outwardly directed transverse bore. No sensor is arranged on the central diaphragm in this measuring device. Instead, a pressure and a pressure difference sensor are fastened parallel to the longitudinal axis of the measurement transducer side-by-side in an inner housing section such that their electrical terminals lie side-by-side in a plane. The electrical terminals of the sensors are connected, in each case, by means of a conductor strip, to an electric lead-through also lying axially parallel next to the sensors.
DE 35 00 613 A1 discloses connecting the bonding wires of a piezoresistive pressure measurement cell directly to the supply lines on a plastic foil material section. However, in this reference, the teaching is not directed to connecting an off the shelf pressure sensor provided with a bonding plate and a housing to an electric lead-through in a simple manner.
Thus, a need still exists to provide a pressure difference measurement transducer which can be manufactured in a relatively simple manner in terms of the arrangement of the electric lead-through.